WIN-T ushers in new dawn for battlefield communications

By David Perera

May 01, 2009

Army Col. William “Chuck” Hoppe leads the Warfighter Information Network-Tactical (WIN-T) program from his post at the Program Executive Office for Command, Control and Communications Tactical at Fort Monmouth, N.J.

A lot is riding on WIN-T, which seeks to bring high-bandwidth, mobile, two-way satellite communications and ad hoc mesh radio connectivity to battlefield commanders. It’s essential to network-centric warfare. Mobile bandwidth connectivity means better situational awareness, which translates into seeing and responding to the enemy before the enemy can attack. After cost overruns, the program was restructured in June 2007 into four increments, each more technologically advanced than the previous one.

Increment 1 evolved from an effort originally called the Joint Network Node-Network. The Army funded JNN-N after the invasion of Baghdad in 2003 made obvious the need for an immediate upgrade in communications ability. JNN-N, or WIN-T Increment 1, is an improvement over the Cold War-era infrastructure it replaced, but it falls short of WIN-T’s goal of mobile networking inside command vehicles without any end-user configuration.

Hoppe spoke with Defense Systems contributing editor David Perera about what’s ahead for the WIN-T initiative.

Catch a waveform

Hoppe said Increment 2 will reach all Army echelons down to the company level, giving them a broadband backbone connection where today they generally have none. The network is designed to let users send and receive voice, video and data transmissions over IP. However, the data rates will vary, Hoppe said. Here’s how he explained it:

“It depends on whether you’re talking on the halt or on the move. Obviously, if you’re stationary, there will be things we can do to the waveform that can give us higher throughput. … But my threshold requirements for Increment 2 at the company level, where they have nothing today, … for on the move are a minimum of 128 kilobits/sec. But then if you’re at the halt, you can get upwards of about 1 megabit.”

Data throughput depends on environmental conditions because bad weather can interfere with signals. However, Hoppe said, the system should achieve the threshold requirements even in heavy rain, for example. And battalions will experience higher data rates than they’re used to.

Hoppe noted that the WIN-T project is developing two waveforms for connectivity — the Network-Centric Waveform (NCW) for satellite connectivity and the Highband Networking Waveform (HNW) for terrestrial radio connectivity.

The speed of battalions’ satellite connection will range from 15 megabits/sec to 22 megabits/sec, although it will be shared across the entire network — what Hoppe called an aggregate rate. The rate for the terrestrial radio waveform will be in the neighborhood of 60 megabits/sec, he added.

Increment 2 will introduce upgrades to Increment 1 capabilities starting at the battalion level, even though they’ll be available only when soldiers are stationary — unlike the NCW and HNW modems, which were designed to work when troops are on the move. The upgrades will add the Multiple Frequency Time Division Multiple Access protocol to existing Increment 1 satellite modems, which at the battalion level are programmed only for TDMA. Frequency Division Multiple Access (FDMA) and TDMA are important signal networking concepts, and Hoppe described them this way:

“Think of TDMA as the old party line. Everybody is sharing it. You get a slice of time on it, whereas with FDMA, you get a dedicated amount of bandwidth. That’s a poor man’s description of it. We don't take away capabilities with Increment 2, we bring additional capabilities.”

As a result, Increment 1 modems at the battalion level will be upgraded to operate at speeds ranging from 4 megabits/sec to 16 megabits/sec.

For brigades, NCW modems will achieve aggregate throughputs ranging from 30 megabits/sec to 34 megabits/sec, and HNW modems will get about 90 megabits/sec. Those numbers are valid when troops are stationary. When they are moving at a rate of 25 miles per hour, satellite modems will achieve a minimum rate of 256 kilobits/sec per link, and terrestrial radio modems will get an aggregate rate of 30 megabits/sec, Hoppe said. A single brigade combat team will be able to support more than 50 WIN-T nodes, he added.

At the division level, aggregate rates for stationary users will be 16 megabits/sec to 20 megabits/sec for Increment 1 modems, 48 megabits/sec to 66 megabits/sec for NCW modems and 90 megabits/sec for HNW modems, he said.

Why it doesn't come easy

When asked to explain why Increment 2 is technologically challenging, Hoppe emphasized the requirement to seamlessly and automatically switch between the different waveforms. The transmission subsystem must integrate satcom and line-of-sight, terrestrial waveforms, he said. Some existing systems might offer mobile bandwidth connectivity with one waveform or the other, but switching between them would require manual intervention, whereas the goal of WIN-T is to have the transmission subsystem automatically choose the best path. He explained a typical scenario in which it might be necessary to switch from a terrestrial to satcom link:

“If you’re on a line-of-sight link and you’re moving, and you drop down into a valley and the person you had line of sight with is on the other side of the valley, you lose that line-of-sight link, you’re out of the network. [With] Increment 2, you’ve got HNW and NCW on the same vehicle. We’re constantly sampling the quality of the link. If that link quality starts to deteriorate, the system automatically sets up a satcom link and cuts you over to satcom. ... So you never drop out of the network even though you’ve dropped down in the valley. And then as you come back out of the valley and you re-establish that line of sight, it breaks down the satellite link and puts you back on the terrestrial link. That is the trick.”

“The other piece goes to the whole network operations … [which] is policy-based. [The HNW radio] has two switches and seven lights on it. There’s no place to set a frequency. ... It’s got an RJ45 jack on it so you can configure it with a laptop, or it can be configured over the air and I can change that weight policy based on netops.”

“That’s what makes WIN-T’s transmission subsystem so much different from what’s out there.”

Terrestrial radio attributes

It’s common to think of WIN-T as mostly a satellite reception project, but satcom will merely be the backup waveform in case the terrestrial, line-of-sight HNW connection drops out. When asked if that makes WIN-T mostly a terrestrial radio program, not a satcom one, Hoppe said:

“Depending on how you look at it, that’s an absolutely correct statement. But now you’ve got to ask … why.”

“Frankly, one of the main differences [between NCW and HNW] is latency. Pure physics says that if I’m going to do a satellite shot upward, I’m going to take at least 260 milliseconds to do that. The electrons only flow so fast. If you were on the network right now and went to a command prompt window and you pinged Google, you’d see an answer come back that is in the 10’s of milliseconds in delay. Over a fiber network in the ground, you’re running very, very fast. You’ve got low latency. It’s the same issue. We would like to keep the network in links that have low latency — those are the terrestrial links — because [then] I’m not having to go up and down over satcom. We weight the links, we go terrestrial first, and if you don’t have a link, then you go up over satcom. The point is you have an option to go up over satcom; otherwise, you’d be out of the network.”

Testing results

Increment 2 and some aspects of Increment 3 underwent significant rounds of testing last fall, Hoppe said. In November, engineers took a brigade’s worth of Increment 2 equipment to Fort Huachuca, Ariz., to test it past the breaking point. From January to March, two units — one in Fort Lewis, Wash., and the other in Fort Stewart, Ga. — trained on the equipment and then put it through a limited user test. The Army Evaluation Center managed the tests, so Hoppe only observed them from a distance.

In fact, a soldier at Fort Lewis took a WIN-T unit onto a local highway and was able to make voice-over-IP calls to the network, Hoppe said.

Defense Department officials will sift through the test results and make a decision about low-rate initial production by the third quarter of the fiscal year, he added. More intermediate testing is planned in preparation for the initial operational test and evaluation, which is scheduled for the first quarter of fiscal 2011. Assuming a successful outcome, the Army will begin equipping units with Increment 2 in the third quarter of that year.

The aspects of Increment 3 that are already undergoing testing relate to network operations. The program doesn’t have a separate Increment 2 network operations development effort. Instead, the Army is pressing forward with Increment 3’s network operations features and dropping mature portions of them into Increment 2 as soon as they’re ready.

Incremental revolution

Hoppe emphasized that even though Increment 2 introduces high-bandwidth, on-the-move networking that dynamically switches between terrestrial and satellite waveforms, Increment 3 has plenty of contributions to make.

“When you get to Increment 3, you have more nodes in the network. You have more paths, you have more redundancy, you have more survivability, that kind of thing.”

“Increment 2 is a two-tiered architecture. It’s either on the ground or it’s over satcom. We talked about the latency that going over satcom introduces. It would be nice if we didn’t have to introduce latency and yet introduce another path. In comes the air tier. Increment 3 is a three-tiered architecture.”

For the air tier, unmanned air systems will be equipped to route WIN-T signals using HNW. However, adding the air tier is more than adding a new path. Systems administrators could end up trying to configure their network operations to favor the air tier to such a degree that they introduce a single point of failure, Hoppe said. As a result, the system will have to weigh the availability and advisability of each of the three routing paths in real time.

The waveforms will have wider bandwidth, too. HNW will have about three times the output per link. At times, NCW will have the capacity to reach up to 12 megabits/sec, Hoppe said. Increment 3 will also connect with Future Combat Systems vehicles, which will get liquid-cooled versions of WIN-T units.

In addition, Increment 3 will unite the NCW and HNW modems into a single unit capable of fitting into the same space as a vehicle-mounted Single-Channel Ground and Airborne Radio System (Sincgars).

“We take those separate terrestrial radios and satcom modems and put them in a military specification chassis that fits in the same space as the current Sincgars installation kits that are inside vehicles. If you can visualize that, that is significant engineering reduction.”

Congressional criticism

Lawmakers have criticized Increment 3 for not being well-defined, an assessment that Hoppe said is based on a misunderstanding.

“Increment 2 has an acquisition program baseline (APB). That means that all the contract reporting — all the spending, all the earned value management stuff, the actual cost to perform — is all reported, and it goes up to Congress as the selected acquisition reports.… Those reports go up periodically, and all that contracting data is in there because I have an APB.”

“Increment 3 has been going through the process of getting an APB, but because there hasn’t been an APB, there hasn’t been a selection acquisition report for people like the Congressional Budget Office to look at. That doesn’t mean that it’s not being managed, it just means that the normal reports the CBO would go look for aren’t there. Increment 3 is on a path to be baselined, just like the other programs were.”

An increment too far?

However, when it comes to Increment 4, Hoppe said officials have not done much planning. The requirements document calls for Increment 4 to connect with high-bandwidth, protected satellite transmissions — capabilities the TSAT program was meant to achieve. That program appears to be canceled because of budget cuts announced in April.

“When there is a protected communications satellite architecture that is going to be able to give us the data rate that we need and be able to do that with a small-aperture, on-the-move antenna, we will be able bring Increment 4. But until that satellite architecture is in place, we won’t be able to bring that capability the way we wanted to.”

Over the years, WIN-T has generated a huge amount of scrutiny and questions about its ability to perform. If there’s a final message Hoppe wants to share, it’s that his program is on the verge on putting significant new capabilities into the hands of soldiers.